The invention relates to a vibration absorbing and reducing device for strung sports rackets, wherein the device is mountable on the racket and comprises an elongate flexible block of viscoelastic material having absorption and vibration reducing characteristics.
Contemporary sports rackets are often made of synthetic or metallic materials as opposed to wood. These constructions have brought about advantages in lightness, power transmission and maneuverability for the player to the detriment of the vibration absorbing and reducing capabilities on impact of a projectile, such as a ball, that the player used to have with wooden rackets.
In order to remedy this problem several solutions have been proposed, for example, vibration absorbing frame inserts, frames made of particular synthetic materials having improved shock absorbing or dissipating properties, and absorbing devices which are applied to the strings of a racket. The latter type of device has been particularly developed in recent years since in theory it permits adjustment of the racket to each user's own particular preferences.
An example of the latter device is illustrated in U.S. Pat. Nos. 4,776,590 and 4,609,194 to Krent, and is described as a cylindrical block of foam which is inserted between two adjacent parallel strings. Upon insertion, the block assumes a generally spherical shape and thereby engages four adjacent strings of both sets of strings or three adjacent strings and the racket frame.
An alternative approach to this particular problem has been described in U.S. Pat. No. 4,732,383 to Ferrari et al. The device of this patent consists of a bar or strap of between five to ten inches in length designed to absorb shock and vibration. In use, the bar is woven over and under the vertical strings in the region between the handle and nearest cross or horizontal string. The ends of the bar are brought through the end spaces between the string and the frame of the racket and tucked under the frame. The bar is comprised of layers of varying frequency absorbing material, the inner layers having a higher density than the outer layer.
Various modifications on this idea have been considered, involving, for instance, the fixing of the ends of the bar or strap using appropriate means, such as hooks or loops, or providing a plurality of transversally extending external spaced ribs, as in the EP patent application No. 0,497,561 to Ool et al., wherein the ribs define stops for locating the strap positively with respect to the longitudinally extending strings, the latter arrangement preventing the strap from shifting laterally during play.
The problem with the abovementioned prior solutions is that none of them completely and effectively grip the strings around their entire circumference. Therefore, they do not procure optimal absorption and reduction of vibrations and energy transmitted via the strings to the player.